Mill race

A mill race is like a special channel that water flows through to make a water wheel turn. You know how when you play in a stream, the water goes down the hill? Well, a mill race is like a special stream that people made so that they could use the water to make things work. It's kind of like when you blow on a pinwheel and it spins around really fast. The water makes the water wheel spin around, and then people can use that spinning to do things like grind grain into flour. So a mill race is kind of like a secret water path that people use to make things go!